The present invention relates to exercise equipment and more particularly, to weight-based resistance to exercise movement.
Exercise dumbbells are well known in the art and prevalent in the exercise equipment industry. Generally speaking, each dumbbell includes a handle and a desired number of weights or plates which are typically secured to opposite sides of the handle. The dumbbell is lifted up subject to gravitational force acting on the mass of the handle and any attached weights.
Some prior art dumbbells are made as fixed weights. Some people prefer fixed weight dumbbells, perhaps because they are simple to use and solid in construction. However, a disadvantage of fixed weight dumbbells is that a set of numerous fixed weight dumbbells is required to obtain a range of weight resistance.
Other prior art dumbbells include handles and weight plates which the user is able to add to and/or remove from the handles. These variable weight dumbbells provide an economy of scale because only a few weights may be combined in a variety of ways to obtain a range of weight resistance. On the other hand, these variable weight dumbbells require time to change between levels of weight resistance (particularly since a change is typically made to each end of two separate handles), and the weight plates present a storage problem, as well.
Still other prior art, adjustable weight dumbbells (and barbells) do not require the user to handle the weight plates during changeovers, and they also maintain the weight plates in orderly fashion when not in use. Examples of these more sophisticated, xe2x80x9cself-adjustingxe2x80x9d free weight assemblies are disclosed in U.S. Pat. No. 4,529,198 to Hettick, Jr. (discloses a barbell assembly having opposite side weights which are maintained in alignment on respective storage members and selectively connected to a handle by means of axially movable springs); U.S. Pat. No. 4,822,034 to Shields (discloses both barbell and dumbbell assemblies having opposite side weights which are maintained in alignment on a shelf and selectively connected to a handle by means of latches on the weights); and U.S. Pat. No. 5,637,064 to Olson et al. (shows a dumbbell assembly having a plurality of interconnected opposite side weights which are stored in nested relationship to one another and selectively connected to a handle by means of a U-shaped pin).
The present invention provides exercise dumbbells which xe2x80x9cself-adjustxe2x80x9din response to rotation of a knob. Many of the features and advantages of the present invention will become apparent from the detailed description that follows.